If you searched, then you'll see constant mention of broken ringlands on the 08+ WRX/STI models. Do some research on the ringland issue and you'll see this issue seems to afflict a lot more Stage II GR (08+ Imprezas) than stock or Stage I cars. The STIs use slightly higher compression pistons and for whatever reason, the reports of busted ringlands on Stage II STIs is significantly higher on those cars than the regular WRX. Many will say it's all in the "tune", but the reality is there have been many Stage II STIs and WRXs, for that matter, than have wrecked the ringlands with perfect tunes. I firmly believe there's a very random hiccup in the fuel delivery system that can momentarily flake out cause a very deadly lean condition.
Buyer beware if you choose to go Stage II. The chances are low something bad will happen, but many cases have been reported on this site and other WRX-based sites and the ringland carnage seems to afflict more Stage II and greater cars than any others.